3GPP (3rd Generation Partnership Project), a standardization organization for third generation mobile communication system, is studying wireless access network for next generation mobile communication system. This wireless access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) or LTE (Long Term Evolution).
The LTE defines reconnection procedure for radio link failure (RLF: Radio Link Failure) that occurs between a wireless communication terminal and Serving eNB (evolved Node B), i.e., a destination wireless base station. By following this defined reconnection procedure, it is not requested to initialize the communication state with the wireless access network and execute initial access connection procedure again, and this reduces the interruption time of a service used by the wireless communication terminal when RLF occurs.
Even when a wireless communication terminal moves to a cell edge where it is difficult to maintain the radio quality, the wireless access network executes handover in order to continue to provide a service with a certain level of quality without reminding the operator of the wireless communication terminal of the movement of the wireless communication terminal. More specifically, the wireless communication terminal notifies the eNB of a Measurement Report including a measured radio quality. Then, the eNB determines whether or not handover is to be executed for the wireless communication terminal that has transmitted the Measurement Report on the basis of the received radio quality. Then, to perform the handover, the Serving eNB connected to the wireless communication terminal executes an HO Preparation procedure, and distributes and sets, in advance, information about handover to a handover target cell and to, in some cases, cells that may be reconnected in accordance with operation condition. The information about the handover is UE context which is information used for reception of connection and reconnection due to handover by the eNB having a handover destination (or reconnection destination) cell, and unless the UE context is obtained, reconnection is not accepted.    Non-patent literature 1 3GPP TS 36.300 V10.0.0 (2010 June), “E-UTRA and E-UTRAN; Overall description; Stage 2”, Sec10.1.6    Non-patent literature 2 3GPP TS 36.331 V9.0.0 (2009 September), “E-UTRA RRC; Protocol specification”, Sec5.3.7    Non-patent literature 3 3GPP TS 23.401 V9.5.0 (2010 June), “GPRS enhancements for E-UTRAN access”, Sec5.3.4